Leaded gasoline containing phosphorus and phosphate



ENG/NE POWER L0$$- PERCENT Oct. 2, 1962 R. B. PAYNE ETAL LEADED GASOLINECONTAINING PHOSPHORUS AND PHOSPHATE Filed Sept. 2, 1959 SPARK PLUGFOUL/N6 i I O BASE LEADED GASOLINE l8 BASE LEADED GASOLINE 0.3 T YELLowPHOSPHORUS BASE LEADED GA$0L/NE* 0.225T YELLOW PHO$PHOPUS+ x 0.075TMETHYL PHOSPHATE a! i it 6 u 5i ENG/NE TEST HOURS d BASE LEADED GASOLINEBASE LEADED GASOLINE+ 0.3T METHYL PHOSPHATE BASE LEADED GASOLINE-I- 0.3TYELLow PHOSPHORUS BASE LEADED GASOLINE- Q/ST YELLow PHOSPHORUS +0./5TMETHYL PHOSPHATE L l: a is /'0 IE #4 OCTANE REQUIRMENT INCREASE AFTER2/0 HOURS INVENTORS RICHARD B. PAYNE ADOLH-l L MRS T /K EVERETT IV. CASEATTORNEYS 3 056 667 LEADED GASOLINE CGIJTAINING PHOSPHORUS AND PHOSPHATERichard B. Payne, Park Forest, and Adolph V. Mrstik and Everett N. Case,Homewcod, Ill., assignors, by mesne assignments, to Sinclair Research,Inc, New York,

NE? a corporation of Delaware Filed Sept. 2, 1959, Ser. No. 837,647 5Claims. (CI. 44-69) This invention relates to improved gasoline which isof high octane number and which has incorporated therein a lead compoundas an anti-knocking agent and an additive combination of yellowphosphorus and a selected methyl phosphate.

In using a gasoline in a spark-ignition internal combustion engine,various problems arise. One of these is ordinary knocking which iscombatted by increasing the octane rating of the fuel. By and large,modern gasolines have an octane number of at least 85 RON, that is, asdetermined by the Research Method. Almost without exception producers ofgasoline use non-hydrocarbon agents to raise the octane number of thegasoline. Generally, this agent is a tetraalkyl lead, especiallytetraethyl lead, usually within the range from about 0.5 to 3.0 cc. pergallon, or even as much as approximately 4.5 cc. per gallon, as aknock-suppressing agent. Tetraethyl lead is the most widely usedanti-knock agent, and is very effective for this purpose: it can raisethe octane rating in a gasoline and when this octane is raised enough,ordinary engine knock is overcome. However, the use of leaded gasolineleads to other problems, among which are pre-ignition, spark plugfouling and octane requirement increase.

Pre-ignition is apparently caused by the presence within the enginecylinder of lead-containing deposits. These deposits are hot and causethe mixture in the cylinder to burn before combustion is initiated atthe proper time by the spark plug. Pre-ignition can be controlled, asthe art is aware, by the addition of phosphorus additives to leadedgasoline. Pre-ignition is evidenced by a ping.

Spark plug fouling is also attributed to lead deposits which seem tocause short circuiting of the spark current in the cylinder, leaving thefuel in some cylinders unignited. A good deal of power loss isattributed to spark plug fouling. If this problem is caused by leaddeposits, the troublesome deposits are probably different from thosewhich cause pre-ignition since additives useful in controllingpre-ignition vary widely in their effectiveness on spark plug fouling.Another problem encountered with the use of leaded gasoline is octanerequirement increase (ORI). Ordinary leaded gasoline causes the engineto need higher and higher octane gasoline in order to prevent ordinaryengine knock. This phenomenon is wellknown in the art but not manyremedies are known.

This invention is directed to a high octane leaded gasoline, i.e.gasoline containing a soluble lead compound such as a tetra lower alkyllead compound, having incorporated therein yellow phosphorus and amethyl phosphate of the type R Where R is phenyl including phenyl groupssubstituted on the ring with up to two lower alkyl (1 to 4 carbon atoms)groups and R is R or methyl or a mixture of the two. The resulting fuelsolves the pre-ignition problem, minimizes spark plug fouling andinhibits octane requirement increase. The results obtained fromincorporating both elemental phosphorus and the methyl phosphate arebetter than merely the cumulative effects from their separateincorporation. The yellow phosphorus and the selected methyl phosphateare incorporated into the gasoline genie rates 3,056,667 Patented Oct.2, 1962 erally in a total amount of from about 0.05 to 2 theory, andpreferably in the amount of from about 0.1 to 0.6 theory, 1.0 theorymeaning that for each three gram atoms of lead present in the tetraalkyllead there are incorporated two gram atoms of phosphorus. 'One theory isbased upon the premise that the phosphorus and the lead in thetetraalkyl lead react in the combustion zone to form leadorthophosphate, Pb (PO Stated somewhat difierently, for each three grammoles of tetraethyl lead present in the gasoline, there is alsogenerally incorporated from about 0.1 to 4 gram atoms of phosphorus andpreferably from about 0.2 to 1.2 gram atoms of phosphorus. The yellowphosphorus is usually incorporated in an amount of about 30 to 85 theorypercent of the total phosphorus, preferably about 40 to 80%: forexample, where the phosphorus totals about 0.3 theories, the gasolinewill have incorporated about 0.09 to 0.25 theories of yellow phosphorusand about 0.05 to 0.21 theories of methyl phosphate.

Suitable methyl phosphate materials for incorporation in the compositionof the invention are commercially available under the trade names ICCNo. 2. and ICC No. 3. The first-named material is a mixture containingpredominantly dimethyl xylyl phosphate, the balance consistingessentially of methyl dixylyl phosphate along with traces of trimethylphosphate and trixylyl phosphate. ICC No. 3 is predominantly diphenylmethyl phosphate with the balance made up of phenyl dimethyl phosphate,triphenyl phosphate and trimethyl phosphate. The preferred lead compoundis a tetra lower alkyl lead, such as tetraethyl lead.

In obtaining the novel composition of the invention the yeliowphosphorus and the phosphate may be incorporated separately or as amixture into'a blend containing all of the gasoline hydrocarbons.Alternatively, each of the phosphorus materials or a mixture of them maybe first incorporated into any one or any combination of the hydrocarboncomponents before final blending, as all that is required to accomplishthe desired result is the incorporation of the phosphorus and phosphatein the leaded gasoline by any convenient route. The following examplesof the composition of the invention are intended to be illustrative onlyand not limiting.

Base gasoline A contained, by volume, 28.4% heavy naphtha reformate,28.4% light fluid catalytically cracked gasoline, 19.0% mixed xylenes,19.0% alkylate and 5.2% butane. It had an API gravity of 51.5, an octanenumber of 104.3 by the Research Method and an octane number of 93.2 bythe Motor Method. The ASTM distillation of gasoline A was as follows, indegrees F.:

Initial boiling point 99 10 percent 136 50 percent 260 r 90 percent---329 End point 388 Base gasoline B contained the same constituents asbase gasoline A, except that the heavy naphtha reformate came from adifferent source. It had the following characteristics:

Base gasoline C was composed by volume of 20% isobutane-butane alkylate,53% heavy naptha reformate, 22% light fiuid catalytically crackedgasoline and 5% assess? butane. Gasoline C had an API gravity of 53.6,an octane number by the Research Method of 101.7 and an octane number bythe Motor Method of 91.8. The ASTM boiling range of the base gasoline Cwas as follows:

F. Initial boiling point 90 percent 118 50 percent 264 90 percent 319End point 381 Each of these base gasolines contained 3 cc. per gallon oftetraethyl lead, which had been added as Motor Mix, a commerciallyavailable tetraethyl lead containing a fixed amount of ahalo-hydrocarbon scavenger.

Into a portion of each base gasoline there were dissolved variousadditives in the amount of 0.3 theory to give the following test fuels:

Samples I, II and III were used in a test for spark plug fouling byusing them in a 1956 Buick test engine. The engine was cycledautomatically between idle and low speed, road load operation. Every 24hours a determination of the braking horsepower of the engine was madeat 3000 r.p.m. and wide open throttle, the test spark plugs replacedwith a set of new plugs, the braking horse- The test on Sample I whichcontained no phosphorus additive was discontinued at 146 hours and a 21%power loss was detected as due to spark plug fouling. Sample II, inwhich yellow phosphorus was incorporated, was tested for 195 hours witha 14% power loss. The test on Sample III incorporating both yellowphosphorus and a predominantly dimethyl xylyl phosphate mixture gaveonly slight indication of spark plug fouling and was halted at 322hours.

These figures show that although a leaded fuel having yellow phosphorusincorporated therein gives less spark plug fouling from that encounteredwhen only the base leaded gasoline is used, its incorporation along witha methyl phosphate even in a very minor amount reduces power loss due tospark plug fouling by a large percentage, which is disproportionate tothe quantity used.

Samples IV to VIII were used to test for octane requirement increase ina 210 hour accelerated manual cycling dynamometer test run on a 1957Cadillac engine. The engine was cycled manually over a range of speedsand road loads, including idle. The octane requirement was determinedevery 42 hours at 1500 r.p.m. full load and 2500 r.p.m. full load untilan equilibrium was reached where no further increase occurred.

A test on a sample of base gasoline B containing no phosphorus additiveshowed an octane requirement increase, after 210 hours, of 11.3, whileSample IV after 210 hours at 1500 r.p.m. showed an octane requirementincrease of only 10.0. The results of tests on the other samples areshown in Table III. The resultant difference between the clean enginerequirement and the equilibrium requirements at each speed are averagedto give Aver- Table III.Dynam0meter 0R1 Test Data1957 Cadillac EngineENGINE OC'IANE NUMBER REQUIREMENT Sample V Sample VI Sample VII SampleVIII Test Hours 1, 500 2, 500 1, 500 2, 500 1, 500 2, 500 1, 500 2, 500r.p.m r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m. r.p.m.

power again determined at 3000 r.p.m. and wide open throttle and thetest plugs reinstalled. The decrease in braking horsepower caused byspark plug fouling is reported in Table II and FIGURE 1 of the drawingsfor each of these three sample gasolines.

Table II.-Percent Decrease in Brake Horsepower Due to Spark Plug Fouling1956 BUICK3000 R.P.M.WIDE OPEN THROTTLE Test Hours Sample I Sample IISample III P 99 5 moocsamme age ORI figures reported in Table III andFIGURE 2 of the drawing.

These figures show the effectiveness of the yellow phosphorus and methylphosphate incorporation in inhibiting octane requirement increase. WhereSample VI, having incorporated therein no elemental phosphorus, wastested the octane requirement was found to increase even more than whenthe base leaded gasoline was used. Where a dimethyl xylyl phosphatemixture or a diphenyl methyl phosphate mixture and yellow phosphoruswere incorporated, the octane requirement increased less than when thebase fuel alone was used, and increased only slightly more than whenyellow phosphorus was incorporated alone in a base leaded gasoline. Itwill also be noted that the octane requirement increase found when usinga composition made according to this invention (Sample VIII) is not theaverage of Samples VI and VII.

At the end of each of these tests pre-ignition determinations wereobtained by running the engine at 1500 r.p.m. and wide-open throttlewith a reference fuel. Table IV gives the highest octane numberreference gasoline to give after-fire when the ignition is turned off at1500 r.p.m. full load. A fuel slightly higher in octane number istherefore required in each case to suppress preignition.

Table IV After running engine on Test No. Octane These results show thatthe composition of this invention is effective in reducing pre-ignitionas well as the other major problems faced by the automobile owner whouses leaded gasoline.

This is a continuation-in-part of our application Serial No. 788,414,filed January 22, 1959.

We claim:

1. A leaded gasoline composition consisting essentially of gasoline,about 0.5 to 4.5 cc. per gallon of tetra lower alkyl lead anti-knockagent and having incorporated therein yellow phosphorus and a methylphosphate of the formula where R is selected from phenyl and phenyl withup to 6 two lower alkyl substituents and R is selected from R and methylin a total of about 0.05 to 2 theories with the yellow phosphorus beingabout 30 to theory percent of the total phosphorus.

2. The gasoline composition of claim 1 wherein the tet-raalkyl leadcompound is tetraethyl lead.

3. The gasoline composition of claim 2 where the gasoline has about 0.1to 0.6 theory of yellow phosphorus and the methyl phosphate incorporatedtherein.

4. The gasoline composition of claim 1 where the methyl phosphate is amethyl Xylyl phosphate.

5. The gasoline composition of claim 1 where the methyl phosphate is amethyl phenyl phosphate.

References Cited in the file of this patent UNITED STATES PATENTS1,913,970 Albers June 13, 1933 2,889,212 Yust et al. lune 2, 19592,892,691 Howell June 30, 1959 2,897,068 Pellegrini et al July 28, 19592,911,431 Orlofl et al. Nov. 3, 1959 FOREIGN PATENTS 27,733 GreatBritain Dec. 2, 1913 683,405 Great Britain Nov. 26, 1952 709,653 GreatBritain June 2, 1954 1,134,156 France Nov. 26, 1956

1. A LEADED GASOLINE COMPOSITION CONSISTING ESSENTIALLY OF GASOLINE,ABOUT 0.5 TO 4.5 CC. PER GALLON OF TETRA LOWER ALKYL LEAD ANTI-KNOCKAGENT AND HAVING INCORPORATED THEREIN YELLOW PHOSPHORUS AND A METHYLPHOSPHATE OF THE FORMULA